1. Field of the Invention
The present invention is related to electrical power sources and, more particularly, is directed towards a novel, hand-cranked electrical power source designed especially for use in emergency situations.
2. Description of the Prior Art
Hand-cranked emergency power sources for generating electrical energy are well known. Prior patents which exemplify such devices include: German Pat. No. 321,548; and U.S. Pat. Nos. 963,412; 2,282,963; and 3,621,398.
Such hand-cranked power sources have been used, for example, to directly power field radios or other similar equipment, or to charge chemical batteries in the field. However, the prior art hand-cranked emergency power sources have enjoyed limited usefullness as a result of their excessive weight and their inability to generate any significant amount of power.
The excessive weight of the prior art generators is largely a result of their heavy planetary gearing systems which are required to step up the speed of the input drive shaft from about 60 r.p.m. to several thousand r.p.m. The limited output power available from the prior art devices results from both inefficiencies in the gearing system, as well as from the use of alnico magnets. The latter have a relatively low energy-product, and therefore must be large in size to generate any significant amount of power. This also contributes undesirably to the excessive weight of such generators.
It therefore may be appreciated that there is a great need for a portable, lightweight, emergency power source, which may be easily manually cranked by one or two persons, and which provides a reasonable amount of power over a short time interval.